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不同温度下叶绿体毫秒延迟发光和质子区域化的关系

任汇淼, 魏家绵, 沈允钢

中科院上海植物生理研究所.上海 200032

摘要

在0-1℃的低温条件下叶绿体毫秒延迟发光的快相明显较室温时的高,说明低温条件有利用水氧化所释放的质子在类囊体膜上形成区域化;磷酸化能在毫秒级范围内就利用水氧化产生的区域化质子合成ATP,使毫秒延迟发光的快相降低。随着温度升高,水氧化产生的区域化易向非区域化质子转变,25℃时毫秒延迟发光的快相主要与膜电位有关而难以观察到水氧化所释放的质子的影响。水氧化产生的质子区域化与叶绿体膜的状态密切相关。

关键词： 叶绿体; 毫秒延迟发光; 快相; 光合磷酸化; 区域化质子; nigericin 温度

On the relationship between the millisecond delayed light emission and licalized proton in chloroplast at different temperatures

Ren Huimiao, Wei Jiamian, Shen Yungang

Shanghi Institute of Plant Physiology,The Chinese Academy of Sciences.Shanghai 200032

Abstract

The Effects of nigericin and valinomycin on the fast phase of millisecond delayed light emission (ms-DLE) in chloroplast and the stimulation of photophosphorylation (PSP) by low concentrations of nigercin were investigated at different temperatures. The relationship between ms-DLE and PSP was also studied at low and room temperatures. The fast phase of ms-DLE decreased with increase of temperature in the range of 0-25℃, but only slightly above 8℃. At a low temperature of 0-1℃, the fast phase of ms-DLE was decreased significantly by nigericin(0.5μmol/L) or valinomycin (0.2μmol/L) and almost completely when both compounds were present. The fast phase of ms-DLE was not or only slightly affected by the same concentration of nigericin, but was almost completely demolished by the same concentration of valinomycin at 25℃. The proceeding of PSP decreased both the fast phase and slow phase of ms-DLE at 0-1℃, while the slow phase only at 25℃. Furthermore, PSP was stimulated by low concentrations of nigericin to a larger extent at 0-1℃ than at 25℃. It is suggested that at lower temperaturesthe protons from water oxidation are more likely to be localized on the thylakoid membranes. PSP can utilize the localizd protons from water oxidation in the millisecond range, which results in a decrease of the fastphase of ms-DLE. The localized proton from water oxidation may shift to thebulk phase to be delocalized protons with an increase of temperature, thereby the fast phase of ms-DLE is affected mainly by the membrane electric potentials and the effect of protons from water oxidation on the fast phase almost disapears at 25℃. When the chloroplast preparation stored in liquid nitrogen was used, the difference between the ms-DLE at different temperatures was not observed any more althrough the PSP activity remained the same as with fresh chloroplast preparation. This fact indicates that whether the protons from water oxidation are localized on the thylakoid membrane is highly dependent on the conditions of chloroplast membrane.

Key words: Chloroplast;Millisecond delayed light emission;Fast phase;Photophosphorylation;Localizedproton;Nigericin

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引用本文：

任汇淼, 魏家绵, 沈允钢. 不同温度下叶绿体毫秒延迟发光和质子区域化的关系[J]. 生理学报 1996; 48 (3): .

Ren Huimiao, Wei Jiamian, Shen Yungang. On the relationship between the millisecond delayed light emission and licalized proton in chloroplast at different temperatures. Acta Physiol Sin 1996; 48 (3): (in Chinese with English abstract).